Ninja is yet another build system. It takes as input the
interdependencies of files (typically source code and output
executables) and orchestrates building them, quickly.

Ninja joins a sea of other build systems. Its distinguishing goal is
to be fast. It is born from Evan Martin's work on the Chromium browser
project, which has over 30,000 source files and whose other build
systems (including one built from custom non-recursive Makefiles) can
take ten seconds to start building after changing one file. Ninja is
under a second.
